This application is based on Japanese Patent Application HEI 10-180866, filed on Jun. 26, 1998, the entire contents of which are incorporated herein by reference.
a) Field of the Invention
This invention relates to transmission techniques, more particularly to transmission techniques for musical tone information.
b) Description of the Related Art
MIDI (Musical Instrument Digital Interface) standard is used in communications between electronic musical instruments. Electronic musical instruments having MIDI interfaces can be connected to other electronic musical instruments with MIDI cables. In other words, the electronic musical instruments can transmit MIDI data via MIDI cables to the others. For example, one electronic musical instrument transmits MIDI data containing information of music performance by a player, and the other electronic musical instrument can receive the MIDI data and sound the musical tone. It means that the performance with one electronic musical instrument enables other electronic musical instruments to sound in real-time.
Further, in a communications network of general-purpose computers, many kinds of information can be communicated. For example, one computer transmits information such as audio data (raw musical tone information), MIDI data, etc. to another computer via a communications network after storing the information in a storage device, such as a hard disk drive, connected to the computer. Another computer receives the information and stores it in its hard disk drive or the like. A general-purpose communications network is used only for communicating information and so its characteristics are different from those of MIDI.
The MIDI standard enables a real-time communication between the electronic musical instruments but is not suitable for a long distance communication and a communication among a multiplicity of nodes. On the other hand, the general-purpose communications network is suitable for a long distance communication and a communication among a multiplicity of nodes, but a real-time communication between the electronic musical instruments is not taken into the consideration.
Multimedia communication using the general-purpose communications network is prevailing. Audio data has relatively a large amount of data because the sampling frequency is set, for example, at 48 kHz. It is difficult to transmit sampled audio data in real-time, especially when a transmitting device has a low processing ability. In this case, reduction in an amount of audio data by culling some audio data may be considerable, though it will cause deterioration of sounds.
Also there is a case wherein audio data are compressed for fast transmission. In this case, it is difficult to transmit sampling audio data in real-time when the compression process takes long time.
An object of this invention is to provide an apparatus that can efficiently transmit musical tone information.
According to one aspect of this invention, there is provided a transmission apparatus comprising: a device which inputs musical tone information; a plurality of processing units which jointly process the musical tone information from said input device in distributed processing; a unit which distributes said musical tone information to said plurality of processing units to have the distributed musical tone information distributedly processed by the plurality of processing units; and a device which transmits said musical tone information processed by the plurality of processing units.
According to another aspect of this invention, there is provided a transmission apparatus comprising: a device which inputs musical tone information; a plurality of processing units which jointly process the musical tone information from said input device in distributed processing; a packet generator which measures an amount of said musical tone information distributedly processed by the plurality of processing units at a predetermined cycle, extracts and packetizes a predetermined amount of the musical tone information into a first packet when the amount of the musical tone information is greater than the predetermined amount, and further packetizes next musical tone information after said predetermined cycle is lapsed from the time corresponding to the last musical tone information of said first packet; and a device which transmits said packets generated by said packet generator.
As above, according to this invention, since the processing of the musical tone information is performed in distributed processing by distributing the information to the plurality of the processing units, load of each processing unit is reduced. A real-time processing of the musical tone information can be realized thereby. In addition, a quality of the musical tone information can be improved by increasing an amount of the musical tone information.
When an amount of the musical tone information, which is measured at the predetermined cycle, is greater than the predetermined amount, information of the predetermined amount is extracted and packetized. The next packetizing process is performed by measuring the amount of information after the predetermined cycle started from the time corresponding to the last musical tone information of said first packet. Since the starting time of said predetermined cycle depends on the amount of the musical tone information in the last packet, an efficient packet-transmission can be performed.